A basic Active Matrix/Organic Light Emitting Diode (AMOLED) pixel driving circuit is a 2T1C pixel driving circuit which has a simple structure. In an AMOLED pixel driving circuit based on low temperature poly-silicon (LTPS), due to problems of LTPS such as non-uniform threshold voltages, a circuit for compensating for threshold voltages of driving thin film transistors (TFTs) is required to be added in pixel design for AMOLED. A typical AMOLED pixel driving circuit with compensation for threshold voltages requires a 6T1C pixel driving circuit or a 5T2C pixel driving circuit, or even more TFTs and/or capacitors. With increasing of the amount of the TFTs and/or capacitors, a larger layout space will be occupied, which makes it difficult to reduce size of AMOLED pixels, i.e., limiting development of the AMOLED pixel driving circuit with high pixel per inch (PPI).